German patent document 3,530,812 and equivalent European patent 232,454 of J. R. Kostorz describe a thermostatic mixing valve intended for domestic bathroom use and that has a housing formed with separate hot- and cold-water input connections and with a tempered-water output connection typically carrying a faucet. A valve body in the housing can move between full-cold and full-hot end positions to admit hot and cold water in different ratios, depending on the desired setting which itself is established by an adjustment knob or lever. A thermostat, which term here means a device capable of changing position or shape dependent on temperature, can act on the valve body to move it so as to keep the temperature of the water downstream of the valve body constant. Normally this thermostat is braced by a return spring with the valve body against the temperature-setting device.
An improvement on this device is described in commonly owned U.S. Pat. No. 4,767,052 of J. R. Kostorz and D. Kahle. It also has hot- and cold-water inlets respectively connectable to pressurized hot- and cold-water lines and also has an outlet. Its housing is formed with respective compartments connected to the inlets and outlet and with hot- and cold-water seats bounding the respective inlet compartments. A valve body is displaceable axially in the housing between one end position engaging the hot-water seat, blocking flow from the hot-water inlet compartment to the outlet compartment, out of engagement with the cold-water seat, and permitting flow from the cold-water inlet compartment to the outlet compartment and an opposite end position engaging the cold-water seat, blocking flow from the cold-water inlet compartment to the outlet compartment, out of engagement with the hot-water seat, and permitting flow from the hot-water inlet compartment to the outlet compartment. On moving between these end positions the valve body passes through intermediate positions permitting flow from both inlet compartments past the respective seats into the outlet compartment. A fitting body fixed in the housing and defining a wall of the outlet compartment is formed with a throughgoing hole opening into the outlet compartment. A thermostat in the outlet compartment is fixed with the valve body to a tubular stem engaged through and limitedly axially movable in the hole of the fitting body. A seal ring engages around the stem to seal the hole and a spring is braced between the housing and the stem outside the outlet compartment to pull the thermostat and valve body into solid engagement with the fitting body. A temperature-selecting mechanism engages via the stem with the thermostat and operatively engages via the thermostat with the valve body.
Other single-control mixing valves are known, for example from European patent 196,000 filed by J. Humpert and M. Pawelzik with a claim to the priority of German 3,510,835 filed 26, Mar. 1985 (see also related U.S. Pat. No. 4,687,925). Such a mixing valve has a base plate adapted to be fixedly mounted on a base fitting, a sleeve centered on an axis, having a lower end rotatably mounted on the base plate for rotation about the axis, having an internally threaded upper end, and formed with a radially open window, a stationary valve plate fixed on the base plate inside the sleeve and formed with at least two incoming liquid ports and one outgoing liquid port spaced therefrom, and a movable valve plate flatly sitting on the stationary plate inside the sleeve and formed with a chamber alignable with the ports therein. The movable plate being angularly and radially displaceable relative to the axis so the chamber variously overlaps and interconnects the ports. A control member is fixed inside the sleeve to the movable valve plate A holddown ring threaded in the upper sleeve end bears axially downward on the member and valve plates and a control lever has an inner end separately pivoted on the control member and on the sleeve about respective pivot axes perpendicular to the axis of rotation of the sleeve and an outer end projecting radially from the sleeve through the window. A housing part engaged in the sleeve axially between the holddown ring and the control member is provided with an extension fitting snugly in the window and a pivot carrying the inner end of the control lever.